Dark artifacts when rendering CAD-type model
Thanks Denis! (I can't comment cause I'm new.)

I think I've got a good solution going:



With the object selected, I went to the the Object Data tab of the Properties Panel, and unchecked Auto Smooth.

Then, like Denis suggested, I added an Edge Split modifier. I checked Edge Angle and set it to 180 degrees.

This will work for me. Does anybody have any other suggestions for future reference?